A scuffle broke out, and a number of protesters were dragged away by police. Five people were arrested: one for criminal damage, one for riotous behaviour, one for failing to remove a face mask and two others for "unrelated matters", police said.

A man and woman attending the show stopped to take a selfie on Collins Street but found themselves surrounded by protesters seconds before police swarmed and shepherded them inside the venue.

Protesters yelled out “you’re a disgrace” and “traitors” as the couple disappeared into the hotel.

Dozens of police arrived outside the Sofitel at 5pm, hours before the controversial British politician was due to speak.

Police outside the Sofitel Hotel.Credit:Justin McManus

A small group of protesters set up on the footpath, with some holding placards with the words "get Nazi scum off our streets" and "Melbourne says no to fascism".

They chanted “no fascism, no fear, Nigel you’re not welcome here” as they approached about 50 police who had formed a barricade at the entrance of the hotel.

A single right-wing protester stormed through the protest but he was quickly restrained by police and dragged out of the crowd.

Police search a man outside the Sofitel Hotel ahead of the protest.Credit:Chris Hopkins

A woman was also arrested by police and dragged into Collins Place by officers as tensions flared.

Mr Farage, the former leader of the UK Independence Party, which led the Brexit campaign, is on a national speaking tour.

The show’s promoter, Damien Costas, who publishes Penthouse Magazine, defended the show and Mr Farage’s right to free speech.

Mr Costas said he’d been working with police in the months leading up to Mr Farage’s engagement to ensure safety measures were met.

“I don’t think there will be violence again ... these things usually happen when two ignorant groups come together,” Mr Costas said ahead of the show. “So far our intelligence says they’re [the protesters] a pretty harmless group. They’re just here to spread their message the same way Nigel is.”

He also dismissed claims he would be footing the bill for security at the event.

“I don’t expect them [police] to charge me at all. We’ve discussed no fees whatsoever and I would actually think that it’s an international disgrace on Victoria if police were to charge a member of the European Parliament for protection,” he said, adding that he believed Mr Farage should have been given federal police protection ahead of Friday’s show.

The Campaign Against Racism and Fascism planned the protest against Mr Farage.

“We want to have an anti-racist, loud vibrant protest, after which we’re going to go over and march over to where Chelsea Manning is due to be doing a live cross,” protest organiser Chris Di Pasquale told radio station 3AW.

“If you’re going to go and support the far-right, you need to know that people are going to oppose that, because the far-right is beyond the pale.”

Ms Manning, who is best known for leaking classified military and diplomatic documents to WikiLeaks, was speaking via satellite to an audience at the convention centre.

Just before 8.30pm, about 40 people staged a protest in support of Ms Manning outside the hotel with protesters holding red placards that read “solidarity with Chelsea.”

Protesters had cleared the area by about 9pm but a strong police presence remained outside the venue.

A man is searched by police in the CBD.Credit:Justin McManus

In a statement, police warned protesters that violent or antisocial behaviour would not be tolerated.

They also warned the public that officers would be stopping pedestrians and drivers in the area bounded by Spring, Bourke, Flinders and Russell streets in the CBD to conduct searches without warrants as is standard police practice for large-scale events, including protests.

That zone remained a "designated area" until 1am Saturday.

The designated area where police will stop and search people without a warrant.Credit:Victoria Police

"Public safety is our number one priority," the statement read.

"We are equipped and well-prepared to deploy resources, respond and intervene where needed. Individuals have the right to lawfully attend events and protests, however, we ask that people do so peacefully and respectfully without impact on the rest of the community."

Promotional material for the visit described Mr Farage as the man who positioned the Brexit referendum "as the start of a global populist wave against the political establishment" and the "great disrupter of British and European politics".

Nigel Farage is on an Australian speaking tour.Credit:Chris Ratcliffe

The European Union MP is now mainly a media commentator, with a daily show on LBC, London’s main commercial talk radio station, plus regular slots on Fox News in the US.

Mr Farage appeared at campaign rallies with Donald Trump during the 2016 election campaign and claimed the Brexit result was the "inspiration" behind the President's win.